<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>纵向布局</title>
    <style>
        .outer {
            width: 100%;
            color: white;
            background-color: black;
        }

        .inner {
            width: 100px;
            height: 200px;
            margin-bottom: 50px;
            background-color: red;
        }
    </style>
</head>

<body>
    <div class="outer">
        <div class="inner"></div>
        <div class="inner"></div>
    </div>

</body>

</html>